1. Field of the Invention
The present invention relates to the production of carbon fibres from coal tar pitch or other strongly aromatic distillation residues.
2. Description of the Prior Art
Carbon fibres having excellent mechanical properties have already been obtained by oxidation and thermal conversion of fibres of organic polymers, such as poly-acrylo-nitrile and rayon. Nevertheless, the cost of fibres obtained in this manner is high because of the cost of the raw materials and the low yield of carbon. Fibres have also been obtained from coal tar pitch by subjecting the pitch to heat treatment at moderate temperature and possibly to other treatments or conditioning, and thereafter melt spinning the pitch so treated at a temperature of the order of 300.degree.C. The fibers so obtained were subjected to oxidation intended to make them infusible, and were then carbonised in air. However, these processes result in fibres of a quality much inferior to that of fibres obtained from textile threads.
It is a main object of the present invention to provide a process producing fibres of improved quality obtained from a coal tar pitch or from a strongly aromatic substance similar to coal tar pitch.